Locomotive



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A. MITCHELL.

2 L QMOTIVB. No. 294.252. Patented Feb. 26,1884.

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A. MITCHELL LOOOMOTIVE. I N0. 294,252 Patented Feb. 26, 1884.

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A. MITOHELL.

LOGOMOTIVE.

No. 294,252. Patented Feb. 26, 1884 UNirn STATES i ATENT much.

ALEXANDER MITCHELL, OF WVILKESJBARRE, PENNSYLVANIA.

LOCOMOTIVE.

SPECIFICATION forming part of Letters Patent No. 294,252, dated February 26, 1884.

Application filed July 31, 1883.

To aZZ whom it may concern.-

Be it known that I, ALEXANDER MITCHELL, of WVilkes-Barre, in the county of Luzerne and State of Pennsylvania, have invented certain new and useful Improvements in Locomotives, reference being had to the accompanying drawings, andto the letters of reference marked thereon.

The object of the invention is to obtain a less rigid length of wheel-base than is found in ordinary forms of locomotives, to adapt the engine for use on roads having steep grades and sharp curves, to decrease flange friction, and to increase thetractive or adhesive power of the engine without injuriously affecting the rail. The advantages derived from increasing the number of bearing-points of the engine upon the rail and distributing the weight of the engine over alarge extent of rail by employing a number of pairs of drivers are well known. The effective and economical tractive power or adhesion of the engine must depend upon the proper distribution of the weight over or upon the rail, and this weight can be increased without danger of deflecting the rail in proportion to thenumber of the drivers or the bearing-points which support the weight of the superstructure. For this and other reasons it has been for many years the practice to employ three, four, five, or more pairs of driving-wheels coupled together by a rod-connection.

My invention relates to a locomotive-engine having three, four, five, or more pairs of driving-wheels, and atruck under each end of the boiler, the rear drivers having plain or flangeless tires. Vhere five pairs of drivers are employed, one or more pairs located between the front pair and that pair situated under or near the front end of the fire-box may be also plain; but it is essential to my invention that in all cases the rear pair of drivers shall be plain. Where five or more pairs of drivers are used the front pair may be plain. In all constructions under my invention the overhang at each end of the boiler is supported by a truck, the truck being constructed to have any of the known sliding, swinging, and rotary motions, and suitably equalized with the front and rear drivingwheels. The invention is not intended to be restricted to the use of any special style of truck,which may consist of one to four (No model.)

I pairs of wheels, with or without a radius-bar.

In the accompanying drawings, Figure 1 is a side elevation of a locomotive-engine having five pairs of drivers. Fig. 2 is a similar view of an engine having four pairs of drivers. Fig. 3 is a similar view of an engine having three pairs of drivers. bodiment of my invention.

Similar letters of reference indicate similar parts in the respective figures.

A is the locomotive-boiler. B shows one of the cylinders. Gand G represent,respectively, the forward and rear trucks, the wheels of which are flanged. D shows the rear pair of driving-wheels, which occupy a position about midway of thelength of the fire-box, and which in all modifications of my invention are plain or without aflange. D is the front pair of drivers.

Referring particularly to Fig. l, the front pair of drivers, D, are flanged. The intermediate pairs ofdrivers, D and D are plain, while the pair D, which are under the fire-box or near its end, are flanged. If desired, the front drivers, D, may be plain, in which case the intermediate pair, Dfiwill be flanged, the pair D plain, and the pair D, which are under the firebox or near its end, flanged. In Figs. 2 and 3 the front pair'of drivers, D, are flanged, as also are the intermediate pair, D.

I am aware that heretofore engines have been constructed with a flat driver at the front of the engine in connection with a front truck; but the results accomplished by such construction are not the same as are effected by my invention. The distance from the center of the front truck-axle to the center of the second driver from the front (said second driver having a flanged tire) is greater than the distance, in my construction, from the center of the rear trucleaxle to the center of the nearest driver having a flanged tire, the distance in the latter case being always at least as much less as the length of the cylinder. here a flanged driver is used in front and a plain driver and a truck in the rear, in accordance with my invention, one truck helps the other to guide the engine, the rigid wheel-base being shorter between the centers of flanged drivers than where flanged, drivers are used front and rear,which is the usual practice on the ordinary Consolidation engines, and no longer than where the Each figure shows an em-' front driver is plain on the said class of engines. Experience has demonstrated that in the Consolidation engines having flat drivers in front the flanges of their drivers are Worn in curving,on account of the distance being too great from the center of the front truck-axle to the center of the second front or nearest flanged driver. The Consolidation engines havingflanged front and rear drivers also wear the flanges and rails on account of the length of rigid wheelbase, which will be obviated by the use, in accordance Wlthdny invention, of flat drivers in connection with a truck at the rear end of the engine.

ALEXANDER MITCHELL. [L. s]

Vitnesses:

J. V. DARLING, Gnono-n H. FISHER. 

